High strength 6XXX series aluminum alloys and methods of making the same

Abstract

Described herein are 6xxx series aluminum alloys with unexpected properties and novel methods of producing such aluminum alloys. The aluminum alloys are highly formable and exhibit high strength. The alloys are produced by continuous casting and can be hot rolled to a final gauge and/or a final temper. The alloys can be used in automotive, transportation, industrial, and electronics applications, just to name a few.

What is claimed is: 
     
       1. A method of producing an aluminum alloy product, comprising:
 continuously casting an aluminum alloy using a belt casting device having a belt thermal conductivity between and including the thermal conductivity of steel and the conductivity of copper to form a slab, wherein the aluminum alloy comprises 0.26-2.37 wt. % Si, 0.06-0.60 wt. % Fe, 0.26-2.37 wt. % Cu, 0.06-0.57 wt. % Mn, 0.26-2.37 wt. % Mg, 0.02-0.21 wt. % Cr, and up to 0.15 wt. % of impurities, and Al; 
 homogenizing the slab by heating to a peak metal temperature (PMT) of 450° C. to 580° C. at a heating rate of 10° C./min to 100° C./min and soaking the slab at the PMT; and 
 hot rolling the slab, after the homogenizing, to a final gauge without cold rolling the slab prior to the final gauge, 
 wherein the slab is devoid of cracks having a length greater than 8.0 mm after the continuously casting and before the hot rolling. 
 
     
     
       2. The method of  claim 1 , wherein the aluminum alloy comprises 0.52-1.18 wt. % Si, 0.13-0.30 wt. % Fe, 0.52-1.18 wt. % Cu, 0.12-0.28 wt. % Mn, 0.52-1.18 wt. % Mg, 0.04-0.10 wt. % Cr, 0.002-0.006 wt. % Zn, 0.01-0.06 wt. % Ti, 0.0006-0.001 wt. % Zr and up to 0.15 wt. % of impurities, and Al. 
     
     
       3. The method of  claim 1 , wherein the aluminum alloy comprises 0.70-1.0 wt. % Si, 0.15-0.25 wt. % Fe, 0.70-0.90 wt. % Cu, 0.15-0.25 wt. % Mn, 0.70-0.90 wt. % Mg, 0.05-0.10 wt. % Cr, 0.002-0.004 wt. % Zn, 0.01-0.03 wt. % Ti, 0.0006-0.001 wt. % Zr and up to 0.15 wt. % of impurities, and Al. 
     
     
       4. The method of  claim 1 , wherein the continuously cast slab is coiled before the step of hot rolling the slab. 
     
     
       5. The method of  claim 1 , further comprising cooling the slab upon exit from a continuous caster that continuously cast the slab. 
     
     
       6. The method of  claim 5 , wherein the cooling step comprises quenching the slab with water. 
     
     
       7. The method of  claim 5 , wherein the cooling step comprises air cooling the slab. 
     
     
       8. The method of  claim 1 , further comprising:
 coiling the slab into an intermediate coil before the step of hot rolling the slab to the final gauge; 
 pre-heating the intermediate coil before hot rolling the slab to the final gauge; and 
 homogenizing the intermediate coil before hot rolling the slab to the final gauge. 
 
     
     
       9. The method of  claim 1 , further comprising:
 solutionizing the aluminum alloy product of the final gauge; 
 quenching the aluminum alloy product of the final gauge; and 
 aging the aluminum alloy product of the final gauge. 
 
     
     
       10. The method of  claim 1 , wherein a cold rolling step is not performed. 
     
     
       11. A method of producing an aluminum alloy, comprising:
 continuously casting an aluminum alloy using a belt casting device having a belt thermal conductivity between (and including) the conductivity of steel and the conductivity of copper to form a slab, wherein the aluminum alloy comprises 0.26-2.37 wt. % Si, 0.06-0.60 wt. % Fe, 0.26-2.37 wt. % Cu, 0.06-0.57 wt. % Mn, 0.26-2.37 wt. % Mg, 0.02-0.21 wt. % Cr, and up to 0.15 wt. % of impurities, and Al; 
 homogenizing the slab by heating to a peak metal temperature (PMT) of 450° C. to 580° C. at a heating rate of 10° C./min to 100° C./min and soaking the slab at the PMT; and 
 hot rolling the slab, after the homogenizing, to a final gauge and a final temper, 
 wherein the slab is devoid of cracks having a length greater than 8.0 mm after the continuously casting and before the hot rolling. 
 
     
     
       12. A method of producing an aluminum alloy product, comprising:
 continuously casting an aluminum alloy in a continuous belt caster having a belt thermal conductivity between and including the conductivity of steel and the conductivity of copper to form a slab, wherein the aluminum alloy comprises 0.26-2.37 wt. % Si, 0.06-0.60 wt. % Fe, 0.26-2.37 wt. % Cu, 0.06-0.57 wt. % Mn, 0.26-2.37 wt. % Mg, 0.02-0.21 wt. % Cr, and up to 0.15 wt. % of impurities, and Al; 
 homogenizing the slab upon exit from the continuous caster by heating to a peak metal temperature (PMT) of 450° C. to 580° C. at a heating rate of 10° C./min to 100° C./min and soaking the slab at the PMT; and 
 hot rolling the slab, after the homogenizing, to reduce a thickness of the slab by at least 50%, 
 wherein the slab is devoid of cracks having a length greater than 8.0 mm after the continuously casting and before the hot rolling. 
 
     
     
       13. The method of  claim 12 , wherein the homogenizing step is performed at a temperature from 500° C. to 580° C.